Stock SMS/MMS app stuck sending large MMS picture, blocks sending of all SMS

When I send a picture via MMS, it sometimes gets stuck sending until it times out. This may not be a surprise if the picture is a bit large. Until the timeout, I can't even send any SMS, the whole queue is stuck. As a user, I probably shouldn't be sending huge files by MMS, but that's how it is. Besides, it sometimes work. Overall, pretty bad user experience. Any idea how to address this and who to blame? Should it work in the first place and this is a MMS issue? What size should be considered too large? Should the SMS/MMS app attempt to resize pictures or warn when the file is larger than a given size? Should the SMS/MMS app at least provide a cancel button to avoid having to wait the whole timeout (maybe 30 minutes, I don't know exactly)? Should the gallery app resize the picture before sharing by MMS? LineageOS 22.2 / Android 15 ----------------------------------------------------------- **Edit** It seems the problem is not related to the picture size. The same happened with a simple SMS with a smiley (is this sent as SMS or MMS ?). The message wouldn't send. It even blocked sending another SMS. I switched off the wifi and the messages were sent. It appears when on wifi, the phone switches to 2G or perhaps no data at all and MMS don't get sent. I just tested and couldn't reproduce, though (I could send a smiley to myself with the wifi on), so it might be a little bit more complicated than this. Is there a setting to let the phone switch to 3G/4G while sending MMS even when on wifi?